What is a tracking poll?

Each night between September 2 and the election, Gallup will conduct interviews with registered voters. Each day until the election, CNN will report the results from the previous two nights. To do so, we will drop the oldest interviews to make room for the most recent ones. In other words, on Thursday we will report the results of the interviews conducted Tuesday and Wednesday. On Friday, we will drop the Tuesday interviews and report the results of the interviews conducted Wednesday and Thursday. On Saturday, we will report the results for Thursday and Friday -- and so on. (In September, we reported each day the results from the previous three nights.)

What's the best way to read the results of a tracking poll?

In tracking polls, the trend counts as much as or more than today's numbers. Tracking poll results reflect an overall pattern of campaign events that are unfolding day by day. This is why AllPolitics always reports the trend across a week or more, rather than just one day's numbers.

If ordinary polls are snapshots of the electorate, tracking polls present a moving picture. But out of context they make no more sense than a single frame from a movie. One example: One week the CNN/USA Today/Gallup tracking poll showed results which included Wednesday and Thursday -- which were two good days for Dole -- and also included Saturday and Sunday -- two good days for Clinton. During that time, the tracking poll accurately reported Clinton's lead ranging from 9 to 22 points. If we had done a regular poll over those four days, we would have shown a 16-point lead -- almost identical to the 15-point lead in an ordinary (non-tracking) ABC poll conducted on those same days.

Day-by-day the tracking poll can only show temporary gains or losses attributable to temporary events. Week-by-week, the tracking poll shows remarkable stability: an 18-point Clinton lead in the first week of September, a 17-point lead in the second week, and 16-point leads in the third and fourth weeks.

To help avoid overemphasis on the horse race and focus instead on what's driving the election, the tracking poll has begun to ask a series of questions on issues and events. When appropriate, we will incorporate these into a daily narrative to help explain the poll numbers.

What is a 'likely voter'?

Most Americans say they will vote, even though turnout is only about
50-55 percent. We ask questions about past voting behavior, interest in
the campaign, etc. to narrow our sample of registered voters down
to a smaller group of people who are likely to vote. That smaller
group represents our "likely voters." Gallup and Yankelovich do this
in different ways, but both techniques result in a more accurate
portrait of the electorate. It is now CNN's policy to switch to likely
voters in the first poll after Labor Day. Since voters only start to pay
attention to the election after the conventions and Labor Day
weekend, this is the earliest possible time to realistically expect a
likely voter model to give an accurate reading.

What is the release schedule?

Results from the CNN/USA Today/Gallup tracking poll will be
released daily between now and the election. Tracking poll results
will be released every weekday at 4 p.m., every Saturday at noon, and
every Sunday at 5 p.m. (All times Eastern) We will get the results up on AllPolitics as soon as possible each day after the numbers are released.